It is now widely accepted that qualitative and quantitative research traditions, rather than being seen as opposed to or in competition with each other ( Hammersley & Atkinson, 1995 ; Furlong, 2004) should be used, where appropriate, in some kind of combination (Bryman & Cramer, 1999; Moore et al., 2003). How this combining is to be understood ontologically, and therefore epistemologically, however, is not always clear. Rather than endlessly discussing the relationship between different approaches, this paper explores some of the assumptions of the ontologies that underpin such apparent differences, arguing that approaches which declare themselves to be distinct theoretically are often surprisingly similar methodologically. It is argued that dominant ontologies and epistemologies struggle with the conceptualisation and representation of particularity, difference, process, interactions through time, multiple and de-centred forms of causation, and dynamic structure. Complexity/dynamic systems theory is then introduced and examined for its potential to offer the basis of a different kind of ontology: one which is able not only to accommodate these things, but which is itself based upon them. In conclusion, the implications of this perspective are discussed in relation to the problems that have been identified, particularly in relation to the conceptualisation of 'context'.